This application is not related to any pending applications.
This application is not referenced in any microfiche appendix.
The instant invention relates in general to fuel cells and in particular to a method and article of manufacturing for replacing ambient air containing oxygen within a fuel cell with an oxygenless gas, such as, but not limited to, propane, helium, or nitrogen.
The practice of inerting a gas into a fuel cell, particularly fuel cells such as aircraft fuel tanks is well known in the art. For example:
U.S. Pat. No. 2,870,936 issued to A. J. Clayton on Jan. 27, 1959 discloses a closed system for venting and inerting aircraft fuel tanks.
U.S. Pat. No. 3,587,618 issued to Richard L. Kenyon on Jun. 28, 1971 discloses a fire and explosion prevention system for aircraft fuel tanks that utilizes an inert gas for pressurizing the fuel tanks and in which means is provided for preventing over-pressurization of the fuel tanks in case of either clogging of vent passages that normally connect the fuel tanks to atmosphere or failure of vent valves to open, hereafter referred to as the xe2x80x9c618xe2x80x9d patent.
Quite distinct from the ""618 patent which uses liquid nitrogen and thus requires refrigeration to maintain the operational effectiveness of such nitrogen, the instant invention utilizes a gaseous form of nitrogen. A further distinguishing characteristic and benefit of the instant invention is its utilization of a containment vessel requiring far less space than any refrigeration unit associated with the ""618 invention. Further, the instant invention eliminates the attendant weight of the ""618 refrigeration unit by replacing the ""618""s liquid nitrogen with a gaseous form of nitrogen contained within a comparatively small pressurized tank.
U.S. Pat. No. 3,590,559 issued to Kenneth R. Bragg et al. on Jul. 6, 1971 discloses an inerting system to prevent fire and explosion within aircraft or other fuel tanks by maintaining in the ullage thereof an inert atmosphere and by removing oxygen from the fuel when pressure on the fuel decreases, as during the climb of aircraft, such removal of oxygen being accomplished by injecting a mixture of fuel and an inert gas into the fuel supply through submerged nozzles.
U.S. Pat. No. 3,732,668 issued to Richard A. Nichols on May 15, 1973 discloses a system for inerting aircraft fuel tanks comprising mixing of the fuel and an inert gas within a tube whereby the inert gas scrubs the fuel of oxygen dissolved therein and dilutes the same, the mixture being discharged from the tube into the fuel tank where the inert gas and the oxygen rise to the tank vapor space where a portion of the same may be vented to atmosphere but in any case the oxygen content in the vapor space is less than about 12 percent whereby flame and explosion cannot propagate within the tank.
U.S. Pat. No. 3,788,040 issued to Kenneth R. Bragg et al. on Jan. 29, 1974 discloses a method of maintaining the ullage of a previously inerted aircraft fuel tank in the inert condition under which combustion cannot take place within the tank during the after filling of the tank with liquid fuel, and during flight of the aircraft. The method utilizes the oxygen lean ullage gases for scrubbing oxygen from incoming fuel during filling of the tank, separating the gases having scrubbed oxygen therein from the incoming fuel and venting the same to the exterior of the tank so as not to raise the oxygen content of the gases remaining in the ullage.
U.S. Pat. No. 4,378,920 issued to Joe N. Runnels et al. on Apr. 5, 1983 discloses a combustibly inert air supply system and method wherein compressed air is directed through an inert gas generator which removes oxygen to produce a nitrogen enriched, combustibly inert air or gas. The converter is sized to only meet the relatively low flow rate requirements of the system during which times the combustibly inert air or gas is delivered directly to a utilization site. The system further includes a high pressure storage container in which a pressurized precharge of the combustibly inert air or gas is stored. Combustibly inert air is released from such high pressure storage container for providing the higher flow rate requirements of the system. The system may be used aboard an aircraft for inerting fuel tanks. It may include a separate compressor for filling the high pressure storage container.
In view of the limitations and disadvantages of the afore cited prior art, it is apparent that what is needed is an improved method and article of manufacture to effect an oxygen deficient fuel cell which will minimize potential for flame and explosion within an aircraft fuel tank. A need met and exceeded by the instant invention.
A method and article of manufacture to effect an oxygen deficient fuel cell which will minimize the potential for flame and explosion occurring within an aircraft fuel tank.
A first containment vessel contains a pressurized oxygen-free gas, such as, but not limited to, propane, nitrogen or helium. The containment vessel is first connected to a pressure regulator via a pressurized conduit. The pressurized conduit can be constructed of any material capable of transporting oxygen-free gas in a pressurized environment. Said conduit is utilized to facilitate the transport of said oxygen-free gas from the first containment vessel to and through a pressure regulator continuing to and through a demand regulator exiting said demand regulator and entering into a fuel cell. The fuel cell also comprises a exiting gas outflow conduit and outflow valve. In an alternative embodiment of the instant invention an oxygen sensor can be attached to either the exiting gas outflow conduit, the outflow valve or integrated within the outflow valve to sample for and signal the presence of oxygen within the fuel cell.
The invention is practiced by charging the internal portion of a fuel cell with a hydrocarbon based fuel, such as but not limited to aviation fuel.
An object of the instant invention is to minimize the potential for flame and explosion occurring within an aircraft fuel tank.
A further object of the instant invention is to eliminate excessive weight restrictions attendant to prior art approaches to minimize the potential for flame and explosion occurring within an aircraft fuel tank.
Yet another object of the instant invention is to provide a comprehensive, yet uncomplicated method and apparatus to effect an oxygen deficient fuel cell.
Other objects and further scope of the applicability of the present invention will become apparent from the detailed description to follow, taken in conjunction with the accompanying drawings wherein like parts are designated by like reference numerals.